Remove second-row cards from home page (#1628)

## Summary

Simplifies the homepage per internal feedback.

## Changes

- Removed unnecessary content cards related to:
  - Core Components
  - Platform 
  - Support

## Impact

This cleanup improves the landing page by eliminating 43 lines of
outdated content, making the documentation more focused and easier to
navigate for users looking for W&B Inference information.

## Files Changed

- `content/en/_index.md` - Removed outdated card sections

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Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: johndmulhausen